Momentum
https://phet.colorado.edu/sims/collision-lab/collision-lab_en.html
Elastic and inelastic collisions
Two carts, change relative mass
http://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/Exploding-Carts
Small fish and big fish, pre/post momenta
http://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/Fish-Catch
Conservation of momentum
https://serc.carleton.edu/dmvideos/players/mm_collides_car.html?hide_banner=true
Conservation of momentum
Drop brick on moving cart, dot diagram, graphs
http://www.physicsclassroom.com/Physics-Interactives/Momentum-and-Collisions/The-Cart-and-the-Brick
Energy in collisions
Energy in collisions